Possum assassins move into town

A Powerful owl in the box ironbark forest near Bendigo.
Picture: Sandy Scheltema

Powerful owls are devastating possum killers. They swoop silently on the unsuspecting marsupial, break its neck with their hand-sized talons, eat its head, then finish the rest off later.

They eat up to 300 possums a year each - which raises the question: could Powerful owls be the answer to Melbourne's dense possum population, scourge of the city's green thumbs?

Well, as it happens, these magnificent birds - Australia's largest owl - are on the move. Once thought to live only in old-growth forests, they have turned up on the urban fringe in increasing numbers.

There have also been yet-to-be-confirmed sightings in Camberwell, Hawthorn and Kew.

Dr Cooke believes they could be moving in to feast on possums. But life in the suburbs is not all it's cracked up to be - Melbourne's Powerful owl population is facing a housing crisis.

Fewer than 500 pairs are left in Victoria. To survive, the owls need large hollows for chick-rearing. In Melbourne, such hollows are rare because they occur only in trees more than 150 years old. With no hollows, the pairs are simply not breeding.

"If we had more hollows in Melbourne we might have some breeding pairs," said Dr Cooke, a Deakin University ecologist.

Many people have asked Dr Cooke if it is possible to build artificial hollows. "It is something we will consider," she said.

Dr Cooke wants people to help her map the owls. After a recent radio interview and local newspaper article she got more than 100 responses, although some were sightings of the much smaller tawny frogmouth.

The urbanisation of Powerful owls has come at a price: Healesville Sanctuary has received a sharp increase in injured birds. "For an endangered species to be coming in in reasonably large numbers it's got to have an impact on the status of the species," said senior veterinarian David Middleton.